Grese for dissimilar metals, rust/water/long time

[Henrik]

Hi guys. I have searched the forums wide and far, but i can´t find a simple answer to this question (i found 1, but that grease is impossible to find)

Im about to put in some tyrolsport C954 bronze alloy bushing that bolts in between the car frame (mild steel) and subframe (alu) to keep it stable.

I know there is a risk of running dissimilar materials together, with corrosion and all that, but i can´t find a simple answer to what i should use? I was about to just use some alu anti seize in between, but someone said a big no no, but not really had any reason why it wouldn´t work, so i thought i ask here first

Ideally it would be rather permanent (or at least as close as possible) doesn´t wash out with water, and has some corrosion resistance or at least can keep the metals seperated so it doesn´t corrode. Its not an issue if its aerosol or wipe on products, as long as it keeps it nice and corrosion free on the car

Hope you guys can help a newbie out and it would be extra bonus points if it was something that was rather easy found in the EU

 

[Dufus2]

You could use "Epoxy Primer" as a barrier between the metals. Antiseize is intended to stop the corrosion with aluminum to steel applications. Utility manufactures semi trailers and they use a plastic washer between bolts and the aluminum body. A plastic gasket is used between truck wheels to stop the crud from welding alloy wheels to steel wheels.

LPS makes a spray stuff that leaves a wax coating and it works well on equipment exposed to the weather. Amsoil has their HD metal protector that is comparable (4X4 guys use it as undercoating).

I don't know why a good quality anti-seize is not acceptable?
Does the dealer have a recommended product to use?

 

[Henrik]

Hi.

I don´t know either, im about to install it and a fellow mechanic just stated it, but he wasn´t sure why, he has just never used it cause his master said it to him when he was learning the ropes.

Plastic isnt an option as i don´t think i have ever seen anything that will be useable

How long will the products hold up, as alu antiseize i have plenty of that laying around in buckets full

Is there one product in particular you would recommend?

 

[Trav]

This works good. It remains pliable long term and doesn't wash off.
You can use white paste from Molykote also.

http://www.amazon.de/gp/product/B00295GV...rd_i=B0052W8JZY

 

[Henrik]

I have read around a little, and i think i have set my point on an anti seize as that seems to be the most suited for my issue.

Then its the question, what anti seize do i use? Should it be alu, copper, nickel, zink or what else there is? Its aluminium, bronze alloy c954 and mild steel into play

 

[Kestas]

To keep the assembly from corroding, the issue is keeping electrolyte (water) from reaching it. You'd have to keep it wet with grease and keep the grease from washing out. Rustproofing seems the best alternative.

 

[buck91]

Since you asked about greases/antiseize my $0.02 would be a good silicone paste. But I agree that should be second, and a nice thick epoxy or other corrosion inhibiting permanent coating should be laid down on each surface (and cured) first.

Alternatively if this is a low splash area maybe something like fluid film work work well- or may be not?

 

[CT8]

Antiseeze with graphite may increase the aluminum corrosion.

 

[Henrik]

Originally Posted By: Kestas
To keep the assembly from corroding, the issue is keeping electrolyte (water) from reaching it. You'd have to keep it wet with grease and keep the grease from washing out. Rustproofing seems the best alternative.


Hi, i just have bad experience with rust proofing as if it doesn´t get kept up (small holes and such) it can actually catch water and keep it moist all the time?

 

[Henrik]

Originally Posted By: buck91
Since you asked about greases/antiseize my $0.02 would be a good silicone paste. But I agree that should be second, and a nice thick epoxy or other corrosion inhibiting permanent coating should be laid down on each surface (and cured) first.

Alternatively if this is a low splash area maybe something like fluid film work work well- or may be not?


Hi.

It will get some water(not pressure washing strenght and so on, but still get the water from the road and tires)

I have looked around the net and have found some products, but im really not sure what to purchase as they all claim they can cure every problem you have, cancer, make my coffee taste better in the morning and so on^^

Do you know any of these products?
Eck anti corrosion http://www.eckcorrosion.com/
Tef gel http://www.tefgel.com/contain.php?param=tefgel_infor
Duralac http://www.llewellyn-ryland.co.uk/duralac.html

And there is a million others in the same league, do you have an example of what you would use or some first hand experience? Hope its not to much to ask, but this is way over my paycheck to even think of these things

 

[Henrik]

Originally Posted By: CT8
Antiseeze with graphite may increase the aluminum corrosion.


I have read around i have maybe come the conclusion that antiseize is okay to use, but its not a "perfect" choice and there is better suited alternatives.

Its amazing how much there is to grease, anti-seize, paste and so on, before this question it was just something standing on the shelf being used were it was stated in the manuals for making the vehicles.....

Manufacture states a little grease will do the trick, but as i have come to learn, grease is much more than a singel product as it would seem.

 

[Kestas]

Originally Posted By: Henrik
Originally Posted By: Kestas
To keep the assembly from corroding, the issue is keeping electrolyte (water) from reaching it. You'd have to keep it wet with grease and keep the grease from washing out. Rustproofing seems the best alternative.


Hi, i just have bad experience with rust proofing as if it doesn´t get kept up (small holes and such) it can actually catch water and keep it moist all the time?

Yes, there is some truth to that... especially if you do it once and consider it done. Over time it'll harden and partially delaminate, making corrosion worse. Rustproofing needs to be refreshed on a timely basis.

 

[Henrik]

And problem with my setup is it requires total subframe removal and 4 wheel alignemt every time for this to happen, and there is nearly 200 dollars in stretch bolts alone for this to be done so i would like it to be more permanent than rust proof

 

[spackard]

I'm leaning towards not using a metal bushing in between your mild steel frame and aluminum subframe. Grease really isn't going to prevent metal-to-metal contact, and galvanic corrosion.

 

[CT8]

If you can get the A&P mechanics to chime in as they about dissimilar metal corrosion and the proper procedures..

 

[PhillipM]

Makes me wonder why they're using bronze for them to start with tbh?!

 

[Ducked]

Don't use anti-seize unless its a PTFE base. They nearly all have potential for electrolytic corrosion (which you already have in spades), because they're a metal base. Nickel-base anti-seize seems seems to be used in marine settings. so probably the least bad, but I still wouldn't use it. Anti-seize isn't for preventing corrosion, its (duh) for preventing seizing and galling.

I'd use water resistant chassis grease, and I'd use polythene film or sheet (from waste plastics) as a thread/bushing protectant. Hunt around to find appropriate grades that'll work in the interfaces. Here in Taiwan, for example, the little bags the 7-11 gives you for takeout coffee are very fine. Clingfilm (Saran wrap in the US?) might be an alternative if you need fine grades. IF there's space for multi-layers, you could perhaps sandwich grease between them, which would probably increase its residence time and the barrier integrity.

PTFE thread tape might be another possibility, and maybe easier to apply, but it doesn't give you a continuous surface, which might be possible with the film, depending on geometry and clearances.

Down the line you might consider painting it with sunflower or canola oil, (which sets, but slowly) as maintenance. I wouldn't (now) use it in the initial assembly because you may want to take it apart sometime.

 

[ac_tc]

Dont overthink this.
- a slab of antisieze on the bolts
- and a Quick spray of the thin wax type antirust protectant
that you buy in sparaycans.

 

[Jetronic]

parts treated with copper grease always come undone again when needed, parts treated with lithium complex grease will eventually seize. untreated parts are a [censored], even after a few months.

I haven't come across corrosion issues when using copper grease, but have read about it. I'd use it anywhere there's no rubber parts coming in contact with it.

you could use underbody coating to seal off the water afterwards, or even a spray wax as used in hollow spaces for rust proofing

 

[Ducked]

Originally Posted By: Jetronic
parts treated with copper grease always come undone again when needed, parts treated with lithium complex grease will eventually seize. untreated parts are a [censored], even after a few months.

I haven't come across corrosion issues when using copper grease, but have read about it. I'd use it anywhere there's no rubber parts coming in contact with it.

you could use underbody coating to seal off the water afterwards, or even a spray wax as used in hollow spaces for rust proofing


You can "get away" with copper grease in many applications, but this one seems to have an especially high risk of electrochemical corrosion, probably outside most peoples experience, so it might be necessary to resort to theory.

Copper grease is, theoretically, rather bad in this application. Other metal-based greases might be less bad (eg zinc, if you can find it) but a solid plastic film is theoretically superior. Its probably going to prevent metal contact, and its probably going to last.

Using Plastidip in combination with the plastic film might be worth considering, but using it in the interfaces would probably make disassembly too difficult.